Manufacture and production of base-exchanging compounds



Patented Sept. 27, 1932 UNITED STATES PATENT; OFFICE THOMAS PERCY Hrnnrrcmoi BIR ENHEAD, HAROLD JOSEPH wHEA'roN, or HALE, ENGLAND. Assreuons T AMEnIcAN DOUCIL COMPANY, or PHILADELPHIA, rENNsYLvANIA,A CORPORATION OF PENNSYLVANIA r mNur-Accrunn ANnrnonucTIoN or BAsE-ExcHANeING COMPOUNDS v No Drawing. Original application filed August" 13, 1923,

Serial N0.-657,206, now Patent No. 1,848,127.

Divided-and this applicationfiled December 24, 1931. Serial No. 583,132.

7 This invention relates to the production of has been claimed in the base-exchanging compounds, or gels, espe? cially applicable to the purification andsoft'enin'g of water, but not necessarily limited thereto. a g

The present application is a division of our earlier application, Serial "No. 657,206, filed August 13, 1923, now Patent 1,848,127grant ed'Ma-r. 8, 1932. I

In the specifications of UnitedStatesLetters Patent Nos; 1,381,777, issued June 14, 1921, and 1,586,764, issued June 1, 1926, are described and claimed the manufacture and production ofbase-exchanging compounds, in the case of theformer patent, by treating a solution of silicate ofsodium withan acid, so as to neutralize a and afterwards drying the gel and washing itto free it from soluble saltand, in the'case of the latter patent, by the employmentwof solutions of sodium silicate and sodium aluminate in; such proportions and under such conditions as to ing compound on; subsequent treatment analogous to that employed in the former CflSG.- v f V v In the parentapplication above-referred to, of which the present application-is a division, we described the production of improved base-exchangingv compounds by mix-,

ing with a solution of sodium silicate a solu tion of certain 7 sodium compounds which may be defined as acidic sodium salts, or salts of complex, or condensed, acids (other than sodium aluminate) such as sodium pyroborate, .or borax, sodiumdichromate, sodium bicarbonate, sodium metaphosphate, sodium dihydrogen'phosphate, sodium pyrosulphate, sodium bisulphate, or sodium bisulphite,

. such salts being alkali. metalsalts in which the simple metal oxide to'acid anhydride,

ratio is smaller than the corresponding ratio in the normal alkali {metal salt of the same constituents.

" J volv'es mixing with the sodium silicate solu portion of the sodium,

produce a base-exchang,

This portion of our invention said parent applica-- e said parent application also disclosed tion solutions. of more than one other salt;

such, for example, as solutions of sodium aluminate. and sodium pyroborate, or of well as the invention of the present divisional application, it should be stated'thatthe proportion to the sodium silicate of the sodium compound; or compounds, thus added will vary, according to the compound, or compounds, employed say from one molecular proportion of the acidic oxide of such added compound, or compounds, to form one molecular proportion to ve molecular proportions ofsilicarp a lThe' concentration of the solutions may be, for instance,-from about 15 to 26, Twaddell for the solution of the. added compound, or compounds, when the. solubility of the compound in cold water, permits. For compounds of comparatively low solubilitya saturated solution may be used and the strength may be varied, for example, a convenient strength is up to 15 Twaddell according to the constituents used) foreach solution, or so-thatthe stiff gel, resulting from the mixed solutions, contains between5 and 15 percent of its weight of total solids.

4 Although we herein mention only sodium salts it is to be understood that, where it is available, potassium silicate can be used and also that where. they are available, the corresponding potassium or ammonium, be used to mix with the'silicate as aforesaid.

As, in using these other salts, it will be undersalts may 7 stood that the amount thereof chemically equivalent to the sodium salts will be used itis unnecessary to give examples of the use of the other salts.

In connection with that phase of our inven-' tion which is to be claimed in thepresent ap plication, the following examples are given,

and it'is to be noted thatthe drying described should be undertaken after the gel becomes i so produced.

hard, and we prefer to conduct the washing 7.

in a current of water to remove the soluble salts under which. treatment it willbreak down from lumps into granules,

Ezmmple 1 Mix 2,400 parts of a solution of sodium silicate (containing 180 parts of silica and 60 parts of sodium oxide) with 6,000 partsjof-a solution containing 808 parts of crystallized borax andto this add immediately,-(-while well stirring), 1,600 parts of a solution of sodium aluminate containing 5 1 parts'of alu-v mina and 54 parts'of sodium oxide. There will thus be produced a loose'homogeneous gel, which is dried and washed as aforesaid.

'Ewample, 2 l

l\/lix5,600 parts of sodium solicate solution (containing 266 parts of silica and' 89parts of sodium oxide) with 1,800 parts of a solution containing 136 parts of sodium carbonate and immediately mix the resulting mixed solutions with 1,600 partsof a solution containing 54 parts ofalumina and 54 parts of sodium oxide. The product is ,a gel which is dried and washed as aforesaid.

Example 3 ix, simultaneously, 5,400 parts of sodium silicate solution (containing 180 parts of silica and parts of sodium oxide), 1,600 parts of sodium aluminate; solution, containing 54: parts of alumina and 54 parts of sodium oxide, and 2,500 volumes of a'solution, containing2 l0 parts of sodium dichromate. The resulting gel is dried and washed as aforesaid; What we claim is:'

1. In the method of manufacturing a base-i exchanging compound in the wetxway, mixmg a solution of an alkali-metal silicate with axsolution of an alkali metal salt'in which the simple alkali metal oxide to acid anhydride ratio is smaller thanthe corresponding ratio in the normal alkali'metal salt'of the same constituents and with a solution of sodium aluminate under conditions,proportions and degreesof concentration which result in the formation of agel' and then in drying thegel 2.- In the method of manufacturing a'baseexchanging compound in thevwetway, mixing a solution of an alkali-metal silicate with a solution of an alkali metal salt in which the simple alkali metal oxide toacid anhydride ratio is smaller than the corresponding ratio in-the normal alkali metal salt of' thesame constituents and with a solution of sodiumg aluminateunder conditions, proportions and degreesof concentration wh1ch result. in the.

mixinga solution of sodium silicate with a formation of a gel and then in drying the gel so produced and in washing the dried prodnot.

13'. As a. new article of manufacture thev product of claim 1. 7

1. As a new article of manufacture the product of claim 2. i

5.. As a new article of manufacture,a baseexchanging compound which has been produced from a gel resulting from the mixture,

under completely gelatinizing conditions, proportions and degrees of concentration, of a solutionof an alkali metal silicate with a solution. ofan alkali metal salt containing one or more'replaceable hydrogen atoms capable of combining with additional alkali metal and with a solution of sodium aluminate. I 7' 6. In themethod of manufacturing a -baseexchanging compound in the wet way, mix ing a solution of sodium silicate with a solution of crystallized borax and with a solu-" tion of sodium aluminate under conditions, proportions and degrees of concentration which result in the formation of a gel and then in drying the gel so produced.

7 In the method of manufacturing a base exchanging compound in the wet way, mixing' a solution of sodium silicate with a solution "of crystallized borax and with a solutionyofsodium aluminate under conditions, proportions and" degrees of concentration whichresult in "the formation of a gel, in drying the gel so produced and in washing the driedlproduct.

'8; 1 Inthe method of manufacturing a' baseexchang-ing compound in the wet way', mi xing "a solution of'sodium silicate with a solution of sodium bicarbonate and with a s0lution'of sodium aluminate under conditions, proportions and de rees of concentration which resulti'n the o-rmation of'a gel and then in drying the gel so produced.

9. In themethod of manufacturing a base exchanging-compound in the wet way, mixing a solution of'sodium silicate with a solution of sodium-bicarbonate and with a solution of sodium aluminate under conditions, proportions, and degrees of concentration which result in the formation of a gel and then-indrying the gel so produced and finally. in washing the dried product.

' 102 In the method of manufacturing a base-exchanging'compound in the wet way,

no solution of sodium dichromate and with a solution of sodium aluminate under condition, proportions and degrees of'concentra tion-whichresultin the formation ofa gel: and" then in drying the gel so produced.

11. In the method of manufacturing a base=exchanging comp ound in the wet-way, 'mixing'a solution of'sodium silicate with a 'solutions'of sodium dichromateandwith a solutionaiof sodiumi'aluminate under 'conditions, proportions and de ees of concentration which result in the drmation of a gel and then in drying the gel so produced and finally in washlng the dried product.

In testimony whereof we have hereunto signed our names. 7

T. P. HILDITGH. HAROLD J. WHEATON.

(Seal) CERTIFICATE OF CORRECTION.

Patent No. 1,879,239. September 27, 1932.

THOMAS PERCY HILDITCH ET AL.

It is hereby certified that errorappears in the printed specification of the above numbered patent requiring correction as follows: Page 2, line 27, for "carbonate" read bicarbonate; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of November, A. D. 1932.

, M. J. n. Moore.

Acting Commissioner of Patents. 

